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Results of study on the carcinogenicity of the artificial sweetener aspartame

The study is currently being published in the European Journal of Oncology and final results will be presented at the 3rd international scientific conference of the Collegium Ramazzini, “Framing the Future in Light of the Past: Living in a Chemical World”, to be held in Bologna, Italy from September 18-21, 2005, the proceedings of which will be published in the Annals of the New York Academy of Sciences. Background. Aspartame is an artificial sweetener consumed by hundreds of millions of people worldwide. It is used in over 6,000 diet products including soft drinks, chewing gum, candy, desserts, yogurt as well as in pharmaceuticals, in particular, syrups and antibiotics for children. The average daily intake of aspartame is calculated to be about 2-3 mg/Kg of body weight, a figure which increases for children and women of childbearing age. Current daily intake allowed by regulatory bodies is 50 mg/Kg of body weight in the US and 40 mg/Kg of body weight the European Union. Prior to the commercialization of aspartame in the 1970s, the manufacturers of the compound conducted various experimental studies on rats and mice to test its carcinogenicity. When taken together, the results of these studies were considered negative with regard to the carcinogenicity of aspartame. Doubts were however raised by some in the scientific community about the conduct of the experiments and the fact that some cases of malignant brain tumors were found among animals treated with aspartame while none were found among the control group. Given the limitations of these studies and the ever growing use of aspartame throughout the years, the European Ramazzini Foundation decided in the late 1990s to plan and perform an experiment that would, based on the total number of animals used, the number of dose levels studied, and the conduct of the experiment according to Good Laboratory Practices, provide an adequate evaluation of the potential carcinogenic effects of aspartame. The CRC/ERF study was conducted on 1800 rats (900 males, 900 females) of the colony used for over 30 years by the Foundation. In order to simulate daily human intake, aspartame was added to the standard rat diet in quantities of 5000, 2500, 100, 500, 20, 4, and 0 mg/Kg of body weight. Treatment of the animals began at 8 weeks of age and continued until spontaneous death. A complete necropsy and histopathological evaluation of tissues and organs was then performed on each deceased animal, for a total of over 30,000 slides examined by microscope. The first results of the experiment show:1) a dose-related statistically significant increase of lymphomas and leukemias in female rats. This statistically significant increase was also observed at a dose level of 20 mg/Kg of body weight, a dose inferior to the accepted daily intake permitted by current regulations (50-40 mg/Kg of body weight); 2)that the addition of aspartame to the diet induces a dose-related reduction in food consumption, without however causing a difference in body weight between treated and untreated animals. The above results demonstrate for the first time that aspartame is a carcinogenic agent, capable of inducing lymphomas and leukemias in female rats, including when administered at dose levels very close to the acceptable daily intake for humans. In addition, the data demonstrate that the integration of aspartame into the diet did not affect the body weight of treated animals compared with untreated animals. As recognized by the International Agency for Research on Cancer (IARC) of the World Health Organization, results of long-term bioassays conducted on rodents (rats and mice) are highly predictive of carcinogenic risk for humans. In light of this fact, the results of the CRC/ERF study on aspartame call for urgent reconsideration of regulations governing its use as an artificial sweetener in order to better protect public health, in particular that of children. Press Contact:Kathryn KnowlesDirector of Resource DevelopmentEuropean Ramazini Foundationdevelopment@ramazzini.it +39 051.6640460